Poly(ethylene terephthalate) abbreviated as PET fibers accounts for the main part of the polyester applied by the textile industry. The fibers are produced by e.g. poly-condensation of terephthalic acid and ethylene glycol, and drawing of fibers from a melt.
Polyester has certain key advantages including high strength, soft hand, stretch resistance, stain resistance, machine washability, wrinkle resistance and abrasion resistance. However, polyester is not so optimal in terms of its hydrophobicity, pilling, static, dyeability, inactive surface as a medium for adhering, i.e., softening or wettability enhancing compounds, lack of breathability and undesirable high shine or luster appearance.
Because of its strength, polyester fabrics and/or garments are subject to pill formation, and possibly the most important of the cloth finishing processes applied to polyester staple-fibre materials are those designed for control of pilling. All staple-fibre materials tend to form small balls or “pills” of entangled fibres at the cloth surface, when subjected to mild abrasion during wash and wear. If the fabric contains a substantial proportion of fibres having high resistance to flexural abrasion, the pills may be retained on the surface of the cloth in sufficient numbers to produce an unpleasant handle and appearance.
Another problem with polyester is that during synthesis of PET, cyclic or linear oligomers of poly (ethylene terephthalate), such as terephtalic acid-bis-2-benzoyloxy-ethylesther (BETEB) and/or cyclic tri(ethylene terephthalate) are formed. These oligomers are partly deposited on machinery and partly staying on/in the fibers. Oligomers tend to give fabrics a grayish appearance. This is due to deposits of oligomers on the surface of the fabric, which is particularly outspoken after high temperature wet processes like high temperature dyeing. The oligomers can be removed by severe alkaline treatment, which results in a significant loss of fiber material. Organic extraction of the oligomers is a technical possibility, but not industrially feasible.
To blend polyester and cotton, it makes up the defect of pure polyester which has a poor wearability, in which the most important property is to make a better hydrophilicity from cotton. On the other hand, the polyester inclusion will provide the fabric with higher strength and better quick-drying property. And since the lower price of polyester fiber, the mills would like to include more polyester in their material compared to pure cotton. Hence such blended textile has been used broader in industry.
The industry has made great efforts to improve the characteristics of polyester/cellulose blend.
Cutinase and cellulase can be used to reduce the pilling formation of polyester and cellulose fabric respectively, so as to improve the quality of the fabric.
Cutinases are known from various fungi, such as a filamentous fungal cutinase, e.g. native to a strain of Humicola or Fusarium, specifically H. insolens such as e.g. H. insolens strain DSM1800 (U.S. Pat. No. 5,827,719), or F. solani pisi. Methods of reducing the pilling propensity of polyester fabrics and/or garments with a terephtalic acid diethyl ester hydrolytic enzyme (ETE hydrolytic enzyme) and/or an ethyleneglycol dibenzyl ester hydrolytic enzyme (BEB hydrolytic enzyme) (WO99/001604), methods for modifying polyester comprising treating polyester with a polyesterase enzyme (WO2001/34899), and enzymatic hydrolysis of cyclic oligomers of poly(ethylene terephthalate), which comprises subjecting the cyclic oligomer to the action of one or more carboxylic ester hydrolases (WO97/27237) have been disclosed.
Cutinase variants have been described such as in WO0192502 wherein H. insolens variants have been disclosed for the treatment of polyester textile.
WO9629397 discloses enzyme preparations with performance in industrial applications such as laundry composition, for biopolishing of newly manufactured textiles, and for providing an abraded look of cellulosic fabric or garment.
WO2010/076388 discloses fungal endoglucanases with substantial performance at low temperatures; the endoglucanases are used for treating cellulosic material, especially in textile industry, e.g. in biofinishing or biostoning.
However, there is continuously a need for improved benefit of enzymatic polyester blend fabric and/or garment treatment, including enhancing the efficiency of the enzymes to their substrates. Thus identification of such enzymes with improved properties for use in methods for treating fabrics would be desirable. At the same time process optimization to obtain better performance of enzymes are also being investigated.